Multiple unit brake

ABSTRACT

A live and dead lever are mounted on one side of a railway truck and pivotally connected at their lower ends to an automatic double-acting slack adjuster. The upper end of the dead lever is pivotally connected to the truck while the upper end of the live lever is pivotally connected to a piston engaged in a cylinder. A trigger lever is located proximate the live lever and pivotally connected at its lower end to a trigger of the slack adjuster. Two braking devices, each engageable with a wheel used to support the truck, are pivotally connected to the levers intermediate their ends. One device is connected to the dead lever and one device is connected to both the live lever and the trigger lever. Mounted proximate the upper end of the trigger lever is an abutment bracket which is used to retard movement of the end beyond a given point.

United States Patent Mulcahy et al.

[ MULTIPLE UNIT BRAKE [72] Inventors: Harry W. Mulcahy; Eldon W.Bushnell, both of Lansing; John W. Kaim, Chicago,

all of I11.

[73] Assignee: AMSTED Industries Incorporated,

Chicago, Ill.

[22] Filed: Dec. 10, 1970 [21] Appl. No.: 96,778

[52] U.S. Cl ..l88/202, 188/52 [51] Int. Cl ..Fl6d 65/56 [58] Field ofSearch ..188/52, 197, 198, I99, 200,

[56] References Cited UNITED STATES PATENTS 2,994,409 8/1961 Simanek..188/52 3,177,985 4/1965 Rauglas ..188/202 PL R 51 July 25, 1972Primary Examiner-Evon C. Blunk Assistant Examiner-Johnny D. CherryAttorney-Walter L. Schlegel, Jr. and John W. Yakimow [5 7] ABSTRACT Alive and dead lever are mounted on one side of a railway truck andpivotally connected at their lower ends .to an automatic double-actingslack adjuster. The upper end of the dead lever is pivotally connectedto the truck while the upper end of the live lever is pivotallyconnected to a piston engaged in a cylinder. A trigger lever is locatedproximate the live lever and pivotally connected at its lower end to atrigger of the slack adjuster. Two braking devices, each engageable witha wheel used to support the truck, are pivotally connected to the leversintermediate their ends. One device is connected to the dead lever andone device is connected to both the live lever and the trigger lever.Mounted proximate the upper end of the trigger lever is an abutmentbracket which is used to retard movement of the end beyond a givenpoint.

4 Claims, 3 Drawing Figures Patented July 25, 1972 2 Sheet -s 1 lllllll2 Sheets-Sheet 2 Patented July 25, 1972 MULTIPLE UNIT BRAKE Thisinvention relates to brake rigging for railway trucks.

The disclosed brake rigging is particularly adapted for railway trucks.It has the advantage of being lighter in weight and lower in cost thanmost of the currently employed clasp and unit brake arrangements. Therigging may be easily and quickly maintained from the side of the truck.

Because of the slack adjuster employed and the novel adjustment linkage,the proper release clearance will be automatically set during the firstbrake application after the brake shoes or the wheels are replaced.

The rigging maintains a constant piston travel resulting in a relativelyconstant braking force. When large amounts of wear occurs such as whensnow brakes are used, the slack adjuster automatically compensates andreturns the piston travel to its predetermined setting during the nextbrake application.

In brief, the present invention comprises two support brackets that maybe mounted on a railway truck. A cylinder is attached to one of thebrackets and has a piston pivotally connected to the upper end of a livelever. The lower end of the live liver is attached to one end of a knownautomatic double-acting slack adjuster. A dead lever has its upper endpivotally connected to the other bracket and its lower end pivotallyconnected to the other end of the slack adjuster. A trigger leverlocated adjacent the liver lever is pivotally connected at its lower endto the trigger of the slack adjuster. A brake head and shoe assembly ispivotally connected to the trigger and live lever intermediate theirends and a second brake head and shoe assembly is pivotally connected tothe dead lever intermediate its ends. The shoes are engageable with thetreads of the wheels supporting the truck. An abutment bracket isprovided adjacent the upper end of the trigger lever to retard movementof the upper end at a given location during movement of the piston. Thetrigger lever pivots about the brake head and shoe assembly moving thetrigger relative to the slack adjuster body causing the slack adjusterto retain its length or permitting it to shorten or to lengthen,depending upon the forces applied, the position of the trigger, and theclearance between the brake shoes and the wheels.

FIG. 1 is a semi-schematic side elevational view illustrating brakerigging which may be mounted upon a railway truck;

FIG. 2 is an end elevational view illustrating the brake rigging at thelive lever; and

FIG. 3 is an end elevational view illustrating the brake rigging at thedead lever.

The figures illustrate portions of railway wheels and 12 which are usedto support a railway truck (not illustrated) in a known manner. Brakerigging 14 is mounted on the truck and includes support brackets 16 and18.

An air cylinder 20 is mounted on bracket 16. The cylinder 20 is adaptedto receive a piston 22 which is pivotally connected to the upper end ofa live brake lever 24. A known automatic double-acting slack adjuster26, similar to the ones i]- lustrated in U.S. letters Pat. Nos.3,298,475, 3,406,794 and 3,442,358, incorporated herein by reference, ispivotally connected to the lower end of live lever 24 and to the lowerend of a dead brake lever 28. The upper end of dead lever 28 ispivotally connected to bracket 18.

The live and dead levers 24 and 28 are respectively pivotally connectedintermediate their ends to brake heads 30 and 32.

Brake shoes 34 and 36 are secured to brake heads 30 and 32 and areadapted to be engaged with the wheels 10 and 12. Spaced hanger levers 38and 40 are mounted on each side of live lever 24 and dead lever 28. Thehanger levers 38 and 40 are pivotally connected at their upper ends tothe brackets 16 and 18 and at their lower ends to the brake heads 30 and32.

The live lever 24 may extend above piston 22 and be adapted to beconnected with a known hand brake arrangement. For simplicity, the handbrake arrangement is represented by pull rod 42.

A single trigger lever 44 is pivotally connected intermediate its endsto brake head 30. The lower end of the trigger lever 44 is pivotallyconnected to the trigger 46 of the automatic double-acting slackadjuster 26. An abutment bracket 48 is secured to bracket 16 proximatethe upper end of trigger lever 44. Adjustment means, illustrated as abolt-nut combination 49 in a slot 50 is provided to locate the abutmentbracket 48 relative to bracket 16. The abutment bracket 48 is providedto resist movement of the top of trigger lever 44 beyond a given point.

In operation, a force is exerted by piston 22 against the upper end oflive lever 24 moving the brake shoes 34 and 36 respectively into contactwith wheels 10 and 12. At the moment of braking, the slack adjuster 26is rigid.

It is understood that the slack adjuster 26 is designed so that iftrigger 46 does not move, relative to the slack adjuster, the slackadjuster will shorten under a compressive load but will not lengthen.Furthermore, a predetermined movement of trigger 46 relative to slackadjuster 26 permits the slack adjuster to lengthen when required.Movement of trigger 46, in excess of the aforementioned predeterminedamount locks the slack adjuster 26 making it a rigid unit incompression. During a brake application, piston 22 moves in a brakeapplying direction, the upper end of trigger lever 44 contacts abutmentbracket 48 moving trigger 46 relative to slack adjuster 26 causing theinternal mechanism in the slack adjuster to unlock allowing the slackadjuster to lengthen if the brake shoes are not engaged with the wheels.

As piston 22 reaches its predetermined travel, trigger 46 has movedrelative to slack adjuster 26 sufficiently to lock the slack adjuster toprevent shortening under the compressive load of the brake application.

If the distance traveled by piston 22 is less than desired,

trigger lever 44 will be out of contact with abutment bracket 48 at thetime brake shoes 34 and 36 begin to engage wheels 10 and 12. During suchengagement compressional forces are exerted on the ends of slackadjuster 26. Because trigger 46 has not moved and due to the design ofthe internal mechanism of slack adjuster 26, slack adjuster 26 willshorten in length thereby forcing the piston 22 to move further awayfrom cylinder 20 to engage the brake shoes 34 and 36. A point will bereached at which contact will eventually be made between the upper endof trigger lever 44 .and abutment bracket 48 causing trigger 46 to moveaway from slack ad- .juster 26. A predetermined amount of triggermovement will cause the slack adjuster 26 to lock and prevent furthershorteningl The slack adjuster 26 will thereafter be rigid duringbraking.

From the foregoing, and the information incorporated by reference, itcan readily be seen that by adjusting the location of abutment bracket48 any desired piston travel may, be achieved. It may be furtherappreciated that trigger lever 44 may be located proximate either wheel10 or wheel 12 with appropriate positioning of the slack adjuster 26.

What is claimed is:

1. In a braking system for a railway truck supported upon wheels, thebraking system having brake'devices adapted to be frictionally engagedwith the treads of the wheels, actuating means having a movable member,a slack adjuster having first and second ends which ,are movable towardand away from each other and which may be locked in a given positionrelative to each other, and a trigger mounted on the slack adjuster forlocking the ends relative to each other and for permitting movement ofthe ends, the trigger being actuated in response to the movement of atrigger lever, the improvement comprismg:

a live brake lever located on the side of the truck and pivotallyconnected to a brake device adapted to be engaged with a first wheel,the live brake lever having an upper end and a lower end, the upper endbeing pivotally connected to the movable member of the actuating meansand the lower end being pivotally connected to the first end of theslack adjuster; a dead brake lever located on the side of the truck andpivotally connected to a brake device adapted to be engaged with asecond wheel, the dead brake lever having an upper end and a lower end,the upper end being pivotally connected to the truck and the lower endbeing pivotally connected to the second end of the slack adjuster;

a trigger lever pivotally connected to one of the brake devices, thetrigger lever having an upper end and a lower end, the lower end beingpivotally connected to the trigger; and

abutment means located proximate the upper end of the trigger lever tocontact the upper end of the trigger lever during movement of the brakelevers and brake devices to move the lower end of the trigger lever andthereby actuate the trigger.

2. In a brake arrangement for a railway vehicle truck having a frame anda pair of supporting wheel and axle assemblies, the combinationcomprising friction means disposed for engagement with respectiveassemblies, power means having a pair of relatively movable parts one ofwhich is pivoted to the frame, a pair of levers pivoted intermediatetheir ends to respective friction means, one of said levers pivoted atone end to the other of said movable parts of said power means, theother of said levers pivoted at one end to the frame, and slackadjusting means interconnecting the other ends of said levers.

3. The invention of claim 2, further comprising trigger means associatedwith said slack adjusting means for selectively locking and unlockingsame so as to control slack adjustment.

4. The invention of claim 3, wherein said trigger means comprises atrigger supported by said slack adjusting means so as to control saidslack adjustment, a trigger lever pivoted at one end to said trigger andpivoted intermediate its ends to one of said friction means, andabutment means supported by the frame proximate the other end of saidtrigger lever for en gagement therewith upon activation of said powermeans.

1. In a braking system for a railway truck supported upon wheels, thebraking system having brake devices adapted to be frictionally engagedwith the treads of the wheels, actuating means having a movable member,a slack adjuster having first and second ends which are movable towardand away from each other and which may be locked in a given positionrelative to each other, and a trigger mounted on the slack adjuster forlocking the ends relative to each other and for permitting movement ofthe ends, the trigger being actuated in response to the movement of atrigger lever, the improvement comprising: a live brake lever located onthe side of the truck and pivotally connected to a brake device adaptedto be engaged with a first wheel, the live brake lever having an upperend and a lower end, the upper end being pivotally connected to themovable member of the actuating means and the lower end being pivotallyconnected to the first end of the slack adjuster; a dead brake leverlocated on the side of the truck and pivotally connected to a brakedevice adapted to be engaged with a second wheel, the dead brake leverhaving an upper end and a lower end, the upper end being pivotallyconnected to the truck and the lower end being pivotally connected tothe second end of the slack adjuster; a trigger lever pivotallyconnected to one of the brake devices, the trigger lever having an upperend and a lower end, the lower end being pivotally connected to thetrigger; and abutment means located proximate the upper end of thetrigger lever to contact the upper end of the trigger lever duringmovement of the brake levers and brake devices to move the lower end ofthe trigger lever and thereby actuate the trigger.
 2. In a brakearrangement for a railway vehicle truck having a frame and a pair ofsupporting wheel and axle assemblies, the combination comprisingfriction means disposed for engagement with respective assemblies, powermeans having a pair of relatively movable parts one of which is pivotedto the frame, a pair of levers pivoted intermediate their ends torespective friction means, one of said levers pivoted at one end to theother of said movable parts of said power means, the other of saidlevers pivoted at one end to the frame, and slack adjusting meansinterconnecting the other ends of said levers.
 3. The invention of claim2, further comprising trigger means associated with said slack adjustingmeans for selectively locking and unlocking same so as to control slackadjustment.
 4. The invention of claim 3, wherein said trigger meanscomprises a trigger supported by said slack adjusting means so as tocontrol said slack adjustment, a trigger lever pivoted at one end tosaid trigger and pivoted intermediate its ends to one of said frictionmeans, and abutment means supported by the frame proximate the other endof said trigger lever for engagement therewith upon activation of saidpower means.